Epithelial invasion through the basement membrane is a crucial process for tumor progression. In this issue (p 1450), Todd Ridky et al. report on the creation of an organotypic culture system that recapitulates features of tumor progression, including epithelial invasion. The image, courtesy of the authors, shows epithelial cells penetrating through a disrupted basement membrane.

The brain is the master regulator of physiology and behavior. This issue focuses on what we know, and what we need to know, to successfully treat a variety of neurological disorders. The cover image is of a pyramidal neuron, courtesy of Thomas Deerinck, University of California–San Diego.

Neuroblastoma is a tumor commonly derived from neuroendocrine cells in the adrenal medulla. In this issue (p 1134), Andrei Goga and his colleagues show that miR-380-5p represses p53 to control cell survival in neuroblastoma. The cover shows cultured human neuroblastoma cells. (Credit: Nancy Kedersha/Science Photo Library)

Neutrophil extracellular traps (NETs) are a newly identified mechanism by which neutrophils capture and kill pathogens. In this issue, Marcos et al. identify CXCR2 as a neutrophil receptor that can trigger NET formation and show that NETs may exacerbate chronic inflammation in cystic fibrosis. The cover image depicts Shigella caught in a NET released by a nearby neutrophil. (Credit: Science Photo Library)

In this issue, Harald Ott and his colleagues report on the creation of a functional, transplantable bioartificial lung (p 927). The cover shows a scanning electron micrograph of human lung. Credit: Eye of Science / Photo Researchers, Inc.

This issue features a method for the rapid dissection of genetic networks through tissue-specific transduction in mouse embryos (p 821). The cover shows lentiviral infection of mouse hair follicles. Transduced cells in the epidermis are labeled with an antibody against E-cadherin. Image courtesy of Elaine Fuchs/Slobodan Beronja (Rockefeller University).

Mutations in mitochondrial DNA can result in a range of devastating diseases. In this issue, Erica Westly writes in a News Feature about the quest of a family affected by mitochondrial disease for government support of studies on these types of disorders. Also in this issue, the Community Corner highlights legal and technical barriers to the application of a promising approach for overcoming mitochondrial disease. The cover shows a scanning electron micrograph of a mitochondrion in an intestinal epithelial cell. Credit: P. Motta & T. Naguro/Photo Researchers, Inc.

Giardia lamblia is an intestinal parasite that evades the immune system by antigenic variation. In this issue, Hugo Lujan and his colleagues show that they can generate a vaccine to protect against Giardia infection by disrupting this process. The cover depicts a scanning electron micrograph of a G. lamblia trophozoite. Credit: Science Source / Photo Researchers, Inc.

Counterfeit drugs are a growing blight on the pharmaceutical landscape. Our special News focus examines the ongoing international efforts to force out fakes. Cover illustration: Eric Collins (www.oobust.com).

In this issue, Gary Nabel and his colleagues report on the development of a potential vaccine against Chikungunya virus (depicted), an insect-borne virus that causes fever in humans (pp 334–338). Image courtesy of Siyang Sun and Michael Rossmann (Purdue University).

Neutrophil elastase degrades IRS-1 and speeds up lung tumor growth, according to a report by Steven Shapiro and his colleagues (pp 219–223). The cover shows a scanning electron micrograph of a small cancerous tumor filling an alveolus of the human lung. Credit: Moredun Scientific/Photo Researchers, Inc.

Extracellular virus assemblies, reminiscent of bacterial biofilms, can mediate cell-to-cell transmission of the virus HTLV-1 (pp 83–89). The cover is a scanning electron micrograph of a primary CD4+ T cell isolated from a person infected with HTLV-1, showing the virus biofilm-like assembly on the cell surface. Image courtesy of Maria-Isabel Thoulouze.